Motion-picture-film misframe detector



April 8 1924. I

D. H. GIBBS MOTION PICTURE FILM MISFRAME DETECTOR Filed May 22. 192

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DWIGHT H. GIBBS, OF SAN FRANCISCO, CALIFORNIA.

MOTION-PICTURE-FILM MISFRAME DETECTOR.

Application filed May 22, 1922. Serial No. 562,658.

T all whom it may concern:

Be it known that I, DWIGHT H. Gases, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented new and useful Improvements in'Motion- Picture-Film Misframe Detectors, of which the following is a specification.

This invention relates to improvements in motion picture films misframe detectors of the type shown in my U. S. Letters Patent No. 1,334,028, issued March 16, 1921.

The term misframe is applied to an imperfect juncture of two separate picture portions of frames of film. The 'misframe causes a series of pictures to be improperly shown on a screen in that the top and bottom of two pictures appear simultaneously on the screen, instead of one picture alone. As it is a common experience that films are occasionally so shown to the annoyance of spectators it has become the practice to carefully inspect films before projecting them upon the screen.

The primary object of the present invention is to provide a simple, small, compact, easily operable and reliable device by means of which misframes may be readily detected by rewinding the film from the used reel onto an empty reel and causing the film tobe moved over the device of the in vention while it is thus rewound, there bein g means provided in my invention to make possible a more accurate and easy detecting of misframes.

Another object of the invention is to provide a misframe of the character described in which pro-vision is made for moving the film over a detecting wheel which 'is constructed so that the film is illuminated from beneath as it passes over the wheel.

The invention possesses other advantages and features some of which, with the fore going will be set forth at length in the following description where I shall outline in full that form of the invention which I have selected for illustration in the drawings accompanying and forming a part of the present specification. In said drawings I have shown one form of the construction of my invention, but it is to be understood that I do not limit myself to such form since the invention as expressed in the claims may be embodied in a plurality of forms.

Referring to the drawing:

Fig. 1 represents a front elevation of the device of my invention, being broken away in part for the sake of clearness of illustration.

Fig. 2 represents a side elevation of the device.

Fig. 3 represents a top plan view showing a section of the film as when being tested.

Referring particularly to the invention shown in the drawing, 1 represents a base mounted upon a shelf or other support 2, and supporting an upright tubular standard 3, the standard 3 being fitted 011 a socket 41- in the base and held therein by a thumb screw 5. A U-shaped bracket 6 is removably secured to the upper end of the standard by means of a set screw 7 and has journaled thereon upon a pin 8, a detecting wheel 9. The film to be tested is moved over the upper side of the wheel 9 and said wheel is slightly wider than the film but of a circumference equal in length to an equal number of frames, for example, eighteen frames of the film. Its circumference is marked with equi-distant transverse lines 10 which may be imprinted or formed as grooves, and is provided between each pair of adjacent lines with a series of sprocket teeth 11, for example, four in each series. These teeth extend about one-sixteenth of. an inch from the circumference and are of a diameter slightly less than the sprocket holes 12 of the film 13 (see Fig. 3). The wheel being wider than the film causes the ends of the lines to appear outside the edges of the films and should coincide with the black lines 1% of demarcation between the adjacent frames of the films.

The present invention difiers from that of my former one, in that I provide a circumferential groove or space 15 between the sides of the wheel, this groove being of such depth that it provides a hub portion 16 centrally through which hub portion the pin 8 passes. The divided thread thus provided in the wheel supports the film but the space between the treads is substantially equal in width to the transverse width of the picture portion of the frames.

Mounted in any suitable manner upon the U-shaped bracket 6 is a lamp socket 17 in which is mounted an incandescent lamp 18. The lamp is disposed above the hub portion 6 but below the upper side of the wheel so as to be clear of the film. The lamp and socket are arranged so that they do not interfere with the rotation of the wheel but the lamp will provide an intense illumination of the film as it passes over the detector wheel. The electrical conductors 19 leading to the socket are directed through the tubular standard, out from the lower portion of the standard and from thence lead to any suitable source of electrical energy. By means of this lamp the detecting of misframes will be made easier since fihn will be illuminated and detection of the lack of registry of the lines 15 of the film with the lines of the wheel may be reliably effected.

In order to hold the film in proper engagement with the wheel, a frame 20 is pivoted at one side of the bracket 6 and has flanged rollers 21 and 22 thereon arranged so that they may be disposed to engage the upper side of the film on opposite sides of the uppermost portion of the wheel. Below the frame 20 and on opposite sides of the wheel are guide rollers 23 and 24: supported by arms 25 extending outwardly from the bracket 6. The film is adapted to pass under these rollers and then over the top of the detector wheel and under the rollers 21 and 22. By this means and the pins 11 the film is maintained in proper registry with the wheel and will not be subject to accidental displacement.

Assuming that the film is arranged as shown in Fig. 3, and as hereinbefore described with relation to the detector wheel, if the operator carefully inspects the film while rewinding it as described, he will immediately detect any lack of registry between the lines of demarcation between the frames and the lines 10 on the detector. The illumination of the film makes possible the ready detection of any lack of registry or frames with the lines 10. By looking at the ends of the lines 10 on the wheel which appear on opposite sides of the film, this detection of any lack of registry may be provided for, but due to the transparency of the film being accentuated by the illumination an easier and more reliable inspection may be carried out by comparing lines 15 of film with the lines 10 under it on the wheel.

The device of my invention will be useful in finding the frame location on film when no picture is shown as in blank leaders and in fade-outs. A fade out is where one scene in a picture fades away to darkness and another scene comes into view. In the dark portion of the film no frame lines are visible. In order to properly splice film which is broken at a dark or blank portion thereof, by placing the part of the film having lines of demarcation thereon in proper registration with the inspection lines on the inspection wheel, the film may be run over the wheel to the point of the fade-out or blank portion near the break and a mark made on the film over the inspection line on the wheel close to the break. This mark will indicate the exact location of the invisible frame line and permit of a proper splicing of the film.

I claim:

1. Means for detecting film misfraines comprising a wheel over which the film trav els, said wheel having a circumference equal in length to a given number of frames on the film and having marks thereon spaced apart a distance equal to the length of frames of the film, so as to register with the lines of demarcation between the frames on the film, said wheel having a space circumferentially thereof over which the film travels and means of illumination within said space to illuminate the film so as to accentuate its transparency.

2. In means for detecting film misframes a wheel over which the film is adapted to be moved, which wheel has marks on the circumference thereof arranged to register with lines of demarcation between frames of the film, and means located within the confines of the wheel for causing that portion of the film passing over the upper side thereof to be illuminated from beneath to accentuate the transparency of the film.

3. Means for detecting misframes in motion picture films comprising a wheel over and upon which the film travels, means on the wheel for engaging the perforations of the film and guiding it over the wheel, said wheel having a double tread and pro viding a space between the tread portions and means of illumination mounted within the space adjacent the upper side of the wheel, said wheel having marks extending transversely thereon which marks film and adapted to aline with uniform spaced lines of demarcation between the frames.

DWIGHT H. GIBBS.

are spaced apart the length of a frame of the 

